1. Field of the Invention
The present invention relates to a display device equipped with a display panel.
2. Description of the Related Art
A plasma display device having a plasma display panel (referred to hereinbelow as “PDP”) as thin color display panel of a large surface area are presently at a stage of manufactured products.
In PDP, a front glass substrate serving as a display surface and a rear substrate are disposed opposite each other via a discharge space enclosing a discharge gas. A plurality of stripe-like row electrodes extending in the row direction on the display surface are formed on the inner surface (surface facing the rear substrate) of the front glass substrate. On the other hand, a plurality of stripe-like column electrodes extending in the column direction on the display surface are formed on the rear substrate. In this case, a pair of adjacent row electrodes (referred to hereinbelow as “row electrode pair”) serve as one display line. Thus, a structure is obtained in which discharge cells serving as pixels are formed in the intersections of each row electrode pair and column electrodes.
In plasma display devices, first, a wall charge is selectively formed inside each discharge cell according to pixel data of each pixel. Then, a sustaining pulse is repeatedly applied to the row electrodes of the PDP, thereby inducing a repeated sustained discharge in discharge cells where the wall charge has been formed and sustaining the light emission state following this discharge.
Here, following the sustained discharge, a sustained discharge current flows in each row electrode. Further, as the screen size of the PDP increases, the length of row electrodes also increases and the resistance thereof rises. Therefore, a comparatively large voltage drop occurs when the sustained discharge current flows in the row electrodes. At this time, each row electrode has different quantity of sustained discharge current and voltage drop, the difference depending on the total number of discharge cells where the sustained discharge has been initiated on the row electrode. Thus, in the display lines with a large number of discharge cells where the sustained discharge has been initiated, the voltage drop is larger than in the display lines with a small number of such discharge cells. Therefore, the light emission luminance following the sustained discharge decreases. The resultant problem is that luminance nonuniformity occurs within one screen.
In order to resolve this problem, an image display device was suggested in which the number of sustaining pulses that had to be applied to a display was changed for each display line based on display data (for example, JP-A-09-38945).
However, complex control is required to change the number of sustaining pulses for each display line, and the adjustment and verification operations necessary therefor are also difficult.
It is an object of the present invention to provide a display device that resolves the above-described problems and in which high-quality image display without luminance nonuniformity can be attained with a simplified configuration.